Engine-shaft counterbalance.



W. G. DUNN.

ENGINE SHAFT COUNTERBALANCE.

APPLICATION FILED JUNE 21,1912.

Q LQ%&@3QD Patented Dec. 4,1917.

2 SHEETS-SHEET 1- w. e. DUNN.

ENGI'N'E SHAFT COUNTERBALANCE.

APPLICATLON FILED JUNE 21. 1917.

Patented Dec. 4,1917

2 SHEETSSHEET 2- specification aateiitecl Tillie tters Patent.

Application filed June $31, Serial tie. M8 M5.

To all whom it may concern: I

Be it known that 1, WILLIAM G. DUNN, a citizen of the United States, residing at Clarinda, in the county of and State of" Iowa, have lnvented certain new and useful Improvements in Engine-Shaft Counter balances; and I do declare the following tobe a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertai'ns to make and use the same.

My invention relates broadly to improvement in the crank shafts of numerous types of engines, and more particularly to a coun ter balancing device for preventing (listen .tion of the shaft by the action of centrifugal force on the several cranksthoreof.

Experiment and observation have taught that engine crank shafts having opposed cranks positioned on a line extending ohliquely across the shaft, are prone to become deflected when the engine is running; at ahigh rate of speed, this being due to the fact that the crank pins seek a common plane of rotation. This action of the pins, must be resisted by the several. hearings, with the result that excessive strain is placed upon the latter so that they are short lived. To overcome this and other disadvantages such as vibration, one object of my invention. is to position a pair of counter balances acent the opposite sides of the shaft and on an oblique line crossing the aforesaid line on which the crank pins are located, said counter balances exerting the same tendency assaid cranks to seek a common rotative plane. By this means, the shaft is so balanced that it practically floats in its hearings.

Another object of the invention is to provide an arrangement of counter balances which are so constructed as to permit easy attachment thereof to engine shafts of the usual construction.

A further object is to so manufacture the counter balances as to render the same interchangeable, thus effectinga great saving in the manufacture and installation of the bit devices.

A still further object of the invention is to provide a system of counter balances which is readily adaptable to crank shafts in which the opposed crank pins are connected by an oblique portion or crank arm.

With the foregoing general objects in view the invention resides in the novel feathe plan tut-es of construction andnnique conihinations of parts to be hereinafter fullv de scribed and claimed, the descriptive riiatter being supplemented by the accompanying n form a. part of as specifii unit in which: I ligure l a side elevation of a portion or a or: '1': shaft showing the application of my invention;

s vertical.

i e l" 'ansverse 9 of l. i

' on the planeo of Fig. l; and p p spec-two view i iof the COUIMQI halaiwcs and its attacnu in the drawiiws above briefly described,

a common t I "I l is shown, said shaft including; lair of era l' arms 2, opposed crank pins carried allyhythe ends of said arms, and one or more oblique portions or crank arr.- i. which. he tween the pins 3 and assist the arnis 2 rying the same. Since the two pins must be spaced loin :udinall on the shaft, pins seek a co ion plane of rotation, when the shaft a: rotating; at a high rate of "iced,

' centrif force is exerted upon s u pins and it to to throw them ontwart. v Us the fact that th pins 3 are so it by the oblique arni i hmvevr, the outw: in, force exerted on sai pins, is not truly radial, but a $031k bina-Zirm between radial and longitudinal. it being not only the weight of thearnis 2, and pins 3 that ten to so love them, but also the Weight of the crank arm 4i, all of these parts sinniltaneously seekinga single plane of rota I in ()lhbl to resist the action shove de scribed, ll employ a pair of counter halancing weights 5.1 which are positioned on opposite sides of the shaft axis and located on line 6 di'liCli crosses the oblique line 7 upon which C section on this being due to the fact t the crank. pins 3 are located, the weight o1; the counter balances being such LO 1, the same tendency as the cranks, to se coininon rotative plane. The force the "weights ii, however, is opposed to exerted on. the crank pins 3 and the 835001-- ated parts, with the result that no deflection of the shaft will take place is rapidly rotated, said shaft being; truly halanccd so that it practically floats in i been ings "without causing undue wear ado ehrust thereon.

Any preferred means could well he eta-- tit ployed for securing the weights in place,

but said weights are by preference equipped with channel members 8 adapted for application to the opposite sides of the crank arm 4 as shown clearly in the drawings, one end of each of said channel members being formed with an arcuate seat 9 for engage ment with the circular end portions of the crank arm 4, adjacent the pins 3. The channel members 8 are shown joined integrally'to the Weights 5, by means ofsuitable webs 10, but it is to be understood that both parts could well be secured together in any other preferred manner. In all cases, however, it is preferable to provide the channel members 8 with outstanding longisecuring the tudinal flanges 12 through which bolts or cap screws 11 extend for drawing said channel members together into contact with opposite sides of the arm a or equivalent part of the crank shaft to which the device may be applied.

When the improved counter balances are to be applied to crank shafts on which the opposed crank pins are connected by oblique crank arms such as that indicated at 4 the channel members 8 will necessarily be disposed in planes at acute angles to those in which the weights 5 are located, but when the. invention is to be used upon crank shafts in which the adjacent.opposed crank pins are connected by an arm positioned otherwise than obliquely, the relation of the channel members and weights must necessarily vary. Said minor changes, however,

lie clearly within the scope of the invention.

From the foregoing, taken in connection with the accompanying drawings, it will be obvious that although my invention is of extremely simple and inexpensive nature, it will be highly eiiicient for the purposes intended and will be applicable to numerous types of crank shafts now in use, without the necessity of altering the construction thereof in any manner whatsoever. Furthermore, it is unnecessary to drill any openings in the cranks or crank pins when counter-balances in place. This is rendered unneccssaryby the provision of the clamps which are formed of the opposed channel members 8, said clamps serving not only to secure the counter balances in place without altering the crank shaft construction, but simultaneously acting to reinforce the portions of the shaft around which they are secured. On account tion as claimed, without sacrificing the principal advantages.

I claim:

1. An engine crank shaft having an oblique crank arm extending to opposite sides of the shaft axis and opposed crank pins on the ends of said arm, a pair of opposed unjoined counter balances disposed on an oblique line crossing said crank arm, said counter balances being spaced longitudinally of the shaft from the inner ends of said crank pins and from the ends of said crank arm, and means for securing said counter balances to said crank arm and at the same time for strengthening said arm.

2. An engine crank shaft having an oblique crank arm extending to opposite sides of the shaft axis and opposed crank pins on the ends of said arm, a pair of opposed unjoined counter balances disposed on an oblique line crossing said crank arm, said counter balances being spaced longi-' tudinally of the shaft from the inner ends of said crank pins and from the ends of said crank arm, a pair of channel members carrying said counter-balances rigidly and applied to opposite sides of said crank arm, said channel members ext-ending substantially throughout the length of said crank arm to strengthen the same, and means for drawing said channel members tightly around said arm.

3. A structure as specified in claim 2, the

inner ends of said crank pins having outstanding rigid collars and said channel members having U-shaped seats at one end in which the inner portions of said collars are snugly received.

l. A crank shaft counter balance comprising a weight, a channel member carried thereby and of a length to receive substantially the full length of a transverse arm of the shaft, and means for secu 'ing said channel member and arm in fixed relation.

5. A crank shaft counter balance comprising a weight, a channel member carried thereby and of a length to receive substantially the full length of a transverse arm of the shaft, a second channel member of equal length for application to the side of the arm remote from the first named channel member, and means for drawing the two members together around said arm.

6. A crank shaft counter balance comprising a pair of channel members for application to opposite sides of a transverse arm of the shaft and of a length to receive substantially the full length of said arms, means for drawing said members together around said arm, and counterbalancing weights carried by said members. i

' 7. A structure as specified in claim 6, one end of each channel member having a U-shapedseat for engagement with collars at the ends of the crank pins of said arm.

8. A crank shaft counter balance comprising'a pair of unjoined counter balances adapted to be positioned on opposite sides of the 'shaft axis, said counter balances being disposed in parallel planes spaced longitudinally, of the shaft, a pair of separate channel members extending obliquely between said counter balances and joined integrally thereto, said members being of a length to extend substantially throughout the length of an oblique crank arm of the shaft when applied to opposite sides of said arm, screw threaded means for drawing said channel members together around said arm,

and a U-shaped seat on one end of each 15 channel member to engage the collars of the crank pins at the ends of said arm.

In testimony whereof I have hereunto set my hand in the presence of two subscribing 

